SUMMARY I use Slackware64-current 15+ GNU/Linux (up-to-date n86) with KDE Plasma 6 (KDEP6) packages though unofficial for testing, many people use the set. When I go/run 'systemsettings -> appearance & style -> colors & themes -> colors' and select another standard theme it shows 'applied' (button text grays) but nothing happens: I select Dolphin (normally changes colours), and exited & restarted Konsole (normally changes colours after restart), but neither changes colours. I can also test FreeBSD 14-stable UNIX (after updating on n86), maybe Devuan 5.01-stable (Debian 12 with SysVInit) or Gentoo 2025-7-n later. STEPS TO REPRODUCE 1. Upgrade KDEP5 to 6. 2. Change standard colour theme such as from Breeze Dark to Breeze Light. 3. Close & reopen everything (systemsettings, Konsole, Dolphin). OBSERVED RESULT No longer changes colour theme. EXPECTED RESULT Change colour theme. SOFTWARE/OS VERSIONS GNU/Linux/KDE Plasma: Slackware64-current 15+ GNU/Linux (n86) / KDEP6.4.2 KDE Plasma Version: 6.4.2 KDE Frameworks Version: 6.15.0 Qt Version: 6.9.1 ADDITIONAL INFORMATION This has been happening since something such as KDEP6.4.1 or 6.1 or earlier (whenever Lucky Cyborg started packaging). Though most else still does what it should, due to severity of affecting user experience (UE) I'll have to immediately switch back to KDEP5 and (also due to some tens of minutes process uninstalling & downgrading/reinstalling); may not get to test much unless a specific test might speed debugging up, but if known by weekend/Friday, I plan to test then.
Thanks for the bug report. This is odd. I can't replicate that here on Plasma 6.4.3 or git-master. Can you see if this same bug happens on a brand new user, created with Plasma 6? It's possible there are old settings or cache files that are interfering.
I used a user account with no GUI configuration dot-files/-directories/-folders and this time was unable to change from Breeze Light to Dark colour theme.
also had no cache
Thanks for replying. It sounds like there's a misconfiguration somewhere or some missing dependency. This suggests there's a packaging issue with your setup. I recommend contacting the maintainer of the packages you're using. Have you tried testing with the other distros you mentioned? FreeBSD in particular would be a good candidate. Can you reproduce with FreeBSD?
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Had same problem on FreeBSD UNIX 14.3-RELEASE (up-to-date 64-bit n86).
This functionality works for me too. It generally works for everyone, or else there's be a flood of bug reports about it. It sounds like you've got a franken-system built from pieces. That means the system integrator is you! Which means the responsibility for troubleshooting integration issues like this also lies with you. :) Do let us know if yo manage to figure out if the problem is traceable to a problem in any KDE code, rather than a local misconfiguration or incompatibility. Thanks!
As said, there was no configuration--tested with new user with complete KDE for both (unofficial) Slackware KDE and (official) FreeBSD, so the problem certainly isn't my system, but I was told now that KDE services are necessary for something as simple as setting a theme, even in other X Window System window managers (WM) & desktop environments (DE) (KDE itself won't start for me in almost a year on either these OS, but that's a separate bug, also not related to compatibility).